• 정보저장시스템학회논문집
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• 제2권2호
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• pp.156-162
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• 2006

In this paper, we have investigated the disc warping in high-speed slim-type optical disc drive. The track density as well as high rotational speed of the information storage devices must be increased to enhance their recording capacity and data transfer rate. Generally, ODD used in the Lap-top computer has small inner space. So, the flow instability of the inner space is increased rapidly with its rotational speed. In extreme case, the flow instability may cause the malfunction of the read/write pick-up of drives. The experiments and numerical analysis were carried out for several cases and the result shows the influence of airflow to the disc warping.

• 융복합기술연구소 논문집
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• 제5권2호
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• pp.1-6
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• 2015

Flying Saucer(flying disk type UFO) is a rotating disk that flies through the air. Thus, the aerodynamical features of the Flying Saucer can be estimated by taking a close look on the aerodynamics of the rotating disk. In the present paper, the aerodynamics of the rotating disk are reviewed focusing on the their application to the possibility of the UFO type VTOL aircraft. Finally, a combination of Avro Aircraft and Frisbee concepts is suggested as a possible new UFO type VTOL aircraft.

• 한국정밀공학회지
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• 제16권6호
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• pp.58-65
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• 1999

The spinning machine has been developed for a bus and truck wheel disc which is manufactured by spinning process method. This machine has the mechanical structure with bed, 2-column, cross head, 2-vertical slide, 2-horizontal slide with forming roller, clamp slide and main spindle similar to large size vertical lathe. Main spindle attached the mandrel is rotated about 500rpm drived by 280kW power DC motor, and a rotating black material pressed on the mandrel with the clamp slide is spinformed by 2-forming rollers which are attached inner end of the 2-horizontal slides. The 2-vertical and 2-horizontal slides are actuated by the hydraulic cylinder which is controlled by the servo valve individially, and these servo valves are controlled by control signal of the CNC controller which is computed with position signal feedbacked from the encoder sensor. The developed machine can manufacture wheel disc of various section profile without mandrel change because section profile is easily modified using program editing in the CNC controller processor. The wheel disc manufactured by spinning process method has many advantages that the endurance is increased by 2 times and the weight is decreased by 30% compared with a conventional disc.

• 대한토목학회논문집
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• 제29권5B호
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• pp.497-502
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• 2009

광촉매에 의한 수처리 방법은 수중에서 오염물질을 직접분해 처리하며 난분해성 유기물 또는 무기물의 분해가 용이하다. 특히 2차 오염물질의 생성이 거의 없는 것이 가장 큰 장점이라 할 수 있다. 하지만 광촉매 형태에 따라 여러 문제가 발생한다. 회전 광촉매 형태는 기존의 문제를 최소화시키고 회전원판법을 적용하여 고도산화처리가 가능하다. 회전광촉매 반응기의 적용을 위해서는 여러 가지 설계와 운전인자 및 특성에 대한 고찰이 필요하다. 본 연구에서는 회전 광촉매를 $TiO_2$ 고정화 작업으로 회전원판법에 적합하게 제작하였다. 이를 이용하여 회전 광촉매 반응에 의한 폐수처리를 수행하기 위한 운전인자들을 도출하였다. 회전 광촉매 $TiO_2$ 함량은 최대 70%가 한계로 나타났다. $TiO_2$ 함유량이 증가할수록 처리효율도 지속적으로 증가되고 있다. 적절한 회전 광촉매는 R4로 $TiO_2$ 함유량 36.8% 이다. 자외선 세기가 증가 할수록 TCODcr의 분해효과는 지속적으로 증가 된다. 다만 적절한 광원의 세기는 경제성을 고려해서 판단하여야 한다. 회전 광촉매의 회전속도가 증가할수록 처리효율은 향상된다. UV lamp를 반응조에 침지시키지 않을 때 회전 광촉매 수심변화는 수심이 50%, 30%, 10%, 70%, 100% 순으로 처리효율이 높게 나왔다. 본 실험을 바탕으로 태양광에서도 유기물을 처리할 수 있는 시스템을 개발에 바탕이 될 것이라 판단한다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1998년도 금형가공 심포지엄
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• pp.28-42
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• 1998

Spinning is one of the incremental forming process by the rotating mandrel and forming roller, and has been applied to manufacturing the wheel disc of automobile to simplify the manufacturing process and to improve the mechanical properties of product. In the proesent study the process variables have been extracted and considered to decide the specification of the spinning machine. The maximum values of working load and power have been evaluated and the blank size has been disigned. The shape and dimensionof forming roller have been designed and the process condition such a s rotational velocity of mandrel and the feedrate of roller have been decided.

• 한국해양환경ㆍ에너지학회지
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• 제2권2호
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• pp.95-102
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• 1999

Various types of oil response equipments and oil recovery vessels are being developed in Korea from the 1990s to respond nil spill accidents. It should be considered prior to the selection of the oil skimmers to make the oil recovery system more efficient at early stage of oil spill accidents. Rotating baldes of vortex skimmer beneath the water surface concentrate oil and draw it into the weir, where it flows to a collection sump. In this study a recently developed Vortex-Disc skimmer(model : VDS-50) is introduced and the performance test results for the skimmer are discussed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.599-604
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• 2000

Excessive vibration magnitude results in serious damage and economic losses in the turbine and generator system. Therefore, it is of importance to evaluate the accurate dynamic characteristics of the system in advance. In this paper, rotordynamic characteristics of both the shrunk-fit disc and welded drum rotors have been investigated to ensure an excellent running behavior of the system in which low-pressure(LP) turbines of a nuclear power plant were retrofitted to improve thermal efficiency and reliability. Analysis shows that the welded drum rotor has good torsional characteristics rather than the shrunk-fit disc rotor. In addition, verification testing of field test was performed to confirm the retrofit. Test results are good agreement with analysis ones.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1996년도 제10회 학술발표회 논문개요집
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• pp.75-76
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• 1996

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.765-770
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• 2000

Hot-wire measurements are reported on the developing turbulent flows subject to plane rate of strain in a rotating $90^{\circ}$ dog bend. The cross-section of the bend varies from $100mm{\times}50mm$ rectangular shape at the bend inlet gradually to the $50mm{\times}100mm$ shape at the bend outlet with remaining a constant area. Data signals from the rotating test section are transmitted through a slip ring to the personal computer which is located at the outside of the rotating disc. 3-dimensional velocity and 6 Reynolds stress components were calculated from the equations which correlate the fluctuating and mean voltage values measured with rotating a slant type hot-wire into 6 orientations. The effects of Coriolis and centrifugal forces on the mean motions and turbulence structures are investigated with respect to rotational speed.

• Journal of Electrochemical Science and Technology
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• 제3권4호
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• pp.165-171
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• 2012

An experimental study of mass transfer to an amalgamated copper rotating disc electrode has been employed to determine an empirical correlation for the mass transfer rate in laminar flow. The study was performed in a three-electrodes configuration using 0.1 M boric acid and 0.1M potassium chloride as supporting electrolyte with Zn (II) concentration in the range (25-100 mg $dm^{-3}$). Polarization curves at different zinc ion concentration are reported. Hydrogen and oxygen reduction has also been considered.The diffusion coefficients and mass transfer coefficient were obtained using limiting diffusion current technique based on zinc ion reduction. A least squares analysis indicates that the laminar flow results for 13067 < Re > 57552 and 550 < Sc > 1390 can be correlated by the following equation with correlation coefficient (CR) equal to 0.98: $sh=0.61Re^{0.5}Sc^{1/3}$.